Clamping mechanism

ABSTRACT

A clamping mechanism for securing a hollow shaft on a solid shaft, the hollow shaft having, at at least one of its ends, an inner cone for receiving an adaptor bushing that has a corresponding outer cone and rests on the solid shaft; and the adapter bushing having an axial longitudinal slot; and a contraction disk, including at least one pressure ring, exerting a contraction force on the hollow shaft with the aid of the at least one pressure ring; and the pressure ring having an axial longitudinal slot.

[0001] The present invention relates to a clamping mechanism.

[0002] A clamping mechanism for joining a hollow part to a solid shaft is known from the German Patent 4230941 C2. It describes fitting a solid shaft into the hollow part without clearance, two conical rings being pressed against each other.

[0003] The force-receiving part (DE 4230941 C2, Figure, reference numeral 19) retains the expansions and deformations of the hollow part caused by this pressing against one another and thus reduces the elasticity of the hollow part.

[0004] It is also disadvantageous that the number of parts is high, and it is costly to manufacture the hollow part and especially two parts (27, 32) having a cone. In addition, during mounting of the clamping assembly, the solid shaft is pressed, and the clamping force or contraction force is produced by movement of the ring (DE 4230941 C2, Figure, reference numeral 33) and of the inwardly-directed flange (DE 4230941 C2, Figure, reference numeral 34). In so doing, the hollow part is shifted axially relative to the solid shaft. This is a considerable disadvantage if the hollow part is used in a gear unit or other device and is held in its axial position by suitable components, e.g., by retaining rings. Considerable forces are then generated which stress the bearings and may lead to their failure.

[0005] In addition, in the region of the force-receiving part (DE 4230941 C2, Figure, reference numeral 19), the hollow part has a stair-step profile of the inside diameter which leads to a stress concentration and therefore represents a possible breaking point.

[0006] A further disadvantage is that when removing or during disassembly, the screws (DE 4230941 C2, Figure, reference numeral 21) must be unscrewed and other screws having a larger thread must be screwed in. Thus, it is necessary to keep such other screws on hand for the disassembly. This requires too much effort and is costly. In addition, during disassembly, the clamping ring (DE 4230941 C2, Figure, reference numeral 33) must be turned in order to offer an opposite surface on the force-receiving part (DE 4230941 C2, Figure, reference numeral 19) to the other screws. This turning is troublesome, particularly when corrosion or changes such as sticking or the like have taken place during the service life.

[0007] Therefore, the object of the present invention is to provide a clamping mechanism which is as inexpensive and easy to handle as possible.

[0008] According to the invention, the objective is achieved in the clamping mechanism for securing a hollow shaft or a hollow part to a solid shaft according to the features indicated in claim 1.

[0009] Essential features of the invention with respect to the clamping mechanism are that the hollow shaft or the hollow part has, at at least one of its ends, an inner cone for receiving an adapter bushing which has a corresponding outer cone and rests on the solid shaft; at at least the one end, a contraction disk, including at least one pressure ring is provided on the hollow shaft or hollow part for exerting a contraction force.

[0010] An important advantage in the invention is that, when securing or tightening the clamping mechanism, it is possible to keep the relative position with respect to the component to be joined as exact as possible. The present invention has the further advantage that the hollow part to be clamped may also be reliably braced radially on solid shafts which are roughly-toleranced and/or are different in the nominal diameter, using an inexpensive and uncomplicated construction which makes due with as many standard component parts as possible and needs only a small mounting length.

[0011] It is also particularly advantageous that a fitting without clearance is feasible in a cost-effective manner using few parts, especially inexpensive standard parts. In this context, a further advantage is that the hollow shaft has an inner cone, which is why stepped profiles do not have to be implemented, and stress concentration is reduced or even completely avoidable. In addition, the inner cone makes the hollow shaft elastic and sufficiently deformable in order to pass on the geometric changes.

[0012] In a further advantageous development, in each case a contraction disk, including at least one pressure ring, is provided at both ends on the hollow shaft or hollow part for exerting a contraction force. In this case, the advantages correspond to the aforesaid advantages.

[0013] In another advantageous refinement, in each case the hollow shaft or the hollow part has at both ends an inner cone for receiving a specific adapter bushing which has a corresponding outer cone and rests on the solid shaft, a clamping ring being provided at the other end for the axial fixation of the corresponding adapter bushing. This clamping ring is advantageously very compact and able to be produced inexpensively, and axially has only a small overall length. In addition, such a clamping ring provided on the appertaining adapter bushing is sufficient, since it only has to produce the hold necessary for the axial fixation of the adapter bushing. The transfer of torque and/or force between the hollow part and the solid shaft is provided by the other adapter bushing having the associated contraction disk. Moreover, an important advantage in this design approach using a clamping ring is also that a cylindrical solid shaft may be used which, especially because of the small processing expenditure, can be produced more inexpensively than a solid shaft having an end stop, thus a non-constant diameter. Therefore, no end stop or shoulder, to be provided at one end, is necessary. Advantageously, the customer is able to shift the hollow shaft, together with the clamping ring and contraction disk, axially to the optimum position on the cylindrical solid shaft. In particular, a customer is also able to utilize a partial cylindrical section of his existing solid shaft and determine the axial position of the hollow shaft independently of any position of a shoulder on the solid shaft.

[0014] In another advantageous development, the contraction force acts in such a way that the inner cone and the outer cone are shrunk onto each other.

[0015] In one advantageous embodiment, the adapter bushing has an axial longitudinal slot, and the contraction disk, including at least one pressure ring, exerts a contraction force on the hollow shaft or hollow part with the aid of the at least one pressure ring, and the pressure ring has an axial longitudinal slot.

[0016] In one advantageous form, the hollow shaft has no slot. This has the advantage that the hollow shaft may be produced inexpensively.

[0017] In one advantageous development, the inner cone of the solid shaft is machined by grinding. Of advantage in this case is that it permits a particularly good fit.

[0018] In one advantageous refinement, the contraction disk includes at least one pressure ring, at least one bracing disk, at least one tightening disk and at least screws. This offers the advantage that a standard contraction disk is usable with standard component parts.

[0019] In one advantageous embodiment, the contraction disk and/or the bracing disk and/or the tightening disk is/are situated axially within the hollow shaft. This has the advantage that the mounting length is extremely short.

[0020] In one advantageous form, the adapter bushing has a collar formed in such a way that during disassembly, extraction is practicable with the aid of the extraction disk. Of advantage in this case is that a very simple and quick disassembly may be carried out without special aids.

[0021] In one advantageous refinement, the extraction disk has screw holes for the screws for tightening the contraction disk, especially during assembly, and further screw holes for the disassembly, loosening the contraction disk and/or the extraction of at least the adapter bushing. In this case, the advantage is that no further screws are needed, and it is not necessary to turn the extraction disk during disassembly.

[0022] In one advantageous development, the solid shaft has an end stop for limiting the axial position of a further adapter bushing. This is an advantage in that the solid shaft is able to be fitted in a simple manner using two adapter bushings of the same kind.

[0023] In one advantageous embodiment, the further adapter bushing has an outer cone and/or a collar. Of advantage here is that the collar is usable for the extraction, and therefore the need for further parts or the use of further tools is eliminated. Furthermore, the outer cone is an easy-to-manufacture means for producing the fit.

[0024] A further advantage is that the same screws are usable during the extraction as during the tightening, thus, the same screws may be used during assembly and disassembly. Moreover, at the same time, no turning is necessary, because suitably positioned screw holes are already present.

[0025] In another advantageous embodiment, at one end of the hollow shaft, a supporting disk is able to be mounted which is detachably connectible to the solid shaft by a tightening screw. Therefore, the hollow shaft may advantageously be centered axially and prestressed with respect to the solid shaft.

[0026] In another advantageous refinement, the cone angle of the outer cone of the adapter bushing is selected in such a way that the adapter bushing is not self-locking. In this embodiment, the supporting disk, together with the tightening screw, additionally produces a mechanical locking. Consequently, such cone angles are also advantageously usable which permit an even easier disassembly.

[0027] In another advantageous refinement, the cone angle of the outer cone of the adapter bushing is selected in such a way that the adapter bushing is self-locking. In this case, it is advantageous that further components for the mechanical locking or the like are not necessary, and therefore simple and inexpensive constructions are possible.

[0028] Further advantages are yielded from the dependent claims.

Reference Numeral List

[0029]1 SOLID SHAFT

[0030]2 HOUSING

[0031]3 HOLLOW SHAFT

[0032]4 ADAPTER BUSHING (slotted)

[0033]5 PRESSURE RING OF THE CONTRACTION DISK (slotted)

[0034]6 BRACING DISK OF THE CONTRACTION DISK

[0035]7 TIGHTENING DISK OF THE CONTRACTION DISK

[0036]8 SCREWS

[0037]9 RETAINING RING

[0038]10 SUPPORTING DISK

[0039]11 ADAPTER BUSHING (slotted)

[0040]12 SHAFT SEALING RING

[0041]13 SEALING RING FLANGE

[0042]14 BEARING OF THE HOLLOW SHAFT

[0043]15 WHEEL

[0044]16 BEARING OF THE HOLLOW SHAFT

[0045]17 SEALING RING FLANGE

[0046]18 SHAFT SEALING RING

[0047]19 SCREW HOLES with screw bore hole

[0048]20 SCREW HOLES with screw tapped hole

[0049]21 AXIAL LONGITUDINAL SLOT of the adapter bushing

[0050]22 END STOP

[0051]23 AXIAL LONGITUDINAL SLOT of the pressure ring

[0052]24 SUPPORTING DISK

[0053]25 TIGHTENING SCREW

[0054]26 CLAMPING RING

[0055]26.A CLAMPING RING contact surface

[0056]26.B CLAMPING RING centering pressure bore hole

[0057]26.C CLAMPING RING axial longitudinal slot

[0058]27 ADAPTER BUSHING

[0059]27.A ADAPTER BUSHING centering cone

[0060]27.B ADAPTER BUSHING outer centering seat

[0061]27.C ADAPTER BUSHING slot

[0062]28. CLAMPING SCREW clamping ring

[0063] The invention shall now be explained in detail with reference to the figures.

[0064]FIG. 1 shows a clamping mechanism of the present invention in plan view and sectional view.

[0065] A hollow shaft 3 is supported in housing 2 by bearings 14, 16. The housing is designed with sealing ring flange 13, 17 and shaft sealing ring 12, 18, respectively, for the sealing. Wheel 15 is disposed on hollow shaft 3. Solid shaft 1 is arranged within hollow shaft 3. During assembly, solid shaft 1 is inserted into hollow shaft 3. Hollow shaft 3 is designed at its one end with an inner cone for receiving an adapter bushing 4. At another location, solid shaft 1 has an end stop 22 to limit the axial position of a further adapter bushing 11. Hollow shaft 3 has an inner cone for receiving adapter bushing 11. The inner cones are in each case ground and designed geometrically in such a way that adapter bushings 4, 11 with outer cone are able to be introduced between solid shaft 1 and hollow shaft 3. Using a contraction disk, which includes a pressure ring 5, a bracing disk 6, a tightening disk 7 and screws 8, the end of hollow shaft 3 on the contraction-disk side is shrunk onto adapter bushing 4 in such a way that the adapter bushing shrinks onto and presses on solid shaft 1. To be able to easily pass on the elastic deformations occurring, adapter bushing 4 has an axial longitudinal slot 21. Thus, adapter bushing 4 draws together in the circumferential direction and presses radially onto solid shaft 1. Therefore, a tight fit with force-locking is achieved. Adapter bushing 11 likewise has an axial slot. This ensures that the adapter bushing already positions itself against solid shaft 1 and hollow shaft 3 in response to small axial forces. During assembly, adapter bushing 11 is first pre-mounted on solid shaft 1. Solid shaft 1 is then inserted, together with adapter bushing 11, into hollow shaft 3. Therefore, from a certain insertion depth, adapter bushing 11 then centers itself and consequently, in particular, solid shaft 1 as well.

[0066] The insertion ends in the axial direction when adapter bushing 11 contacts the shoulder formed as end stop 22. Thereupon, in the case of the contraction disk, a bracing disk 6 and a tightening disk 7 are moved towards each other by the tightening of screws 8, bracing disk 6 and tightening disk 7 being disposed on a pressure ring 5 having a double outer cone.

[0067] Pressure ring 5 rests with its inner side, thus, its inner cylinder, on hollow shaft 3 and has an axial longitudinal slot. Therefore, with increasing tightening of screws 8, bracing disk 6 and tightening disk 7 press ever more onto pressure ring 5, which thus contracts in the circumferential direction and presses onto hollow shaft 3. Particularly because of the inner cone, this region of the hollow shaft is sufficiently thin-walled and elastic, such that the deformation of this region of hollow shaft 3 causes adapter bushing 4 to shrink.

[0068] In the plan view drawing of FIG. 1, at a screw hole 19, associated screw 8 is depicted in the removed state.

[0069] During disassembly, screws 8 are unscrewed from screw holes 19 and screwed into other screw holes 20 which are staggered at the periphery of tightening disk 7 in such a way that no correspondingly associated screw holes are located in bracing disk 6. Consequently screws 8 are braced against bracing disk 6 for the extraction of tightening disk 7. A supporting disk 10 and a retaining ring 9 establish the axial position of bracing disk 6. At its thicker-walled end, adapter bushing 4 has a collar having an outer diameter such that tightening disk 7 pulls out adapter bushing 4. Consequently, the same screws are useable for the tightening and the extraction.

[0070] Tightening disk 7 is arranged within the axial region of hollow shaft 3.

[0071] With the aid of the present invention, given the same hollow shaft, various solid shafts are usable when working with the clamping mechanism according to the invention, since even if the nominal diameter of the solid shaft is roughly toleranced, the contraction disk joins the hollow shaft to the solid shaft by way of adapter bushing 4. The appertaining tolerance range is a function at least of the elasticity of hollow shaft 3 and the slant of the cone.

[0072] Thus, the present invention offers important advantages, in that given different nominal diameters of solid shaft 1, the same hollow shaft 3 may nevertheless be used. In this context, all other parts are also reusable, with the exception of adapter bushings 4, 11.

[0073] This is particularly advantageous for a manufacturer of devices having a hollow part, the manufacturer supplying customers who use solid shafts having nominal diameters according to the metric or according to the inch system. Using the present invention, after exchanging the, for example, metric adapter bushings for adapter bushings having an inside diameter measured in inches, complete compatibility and utilization are given.

[0074] In addition, roughly-toleranced solid shafts 1, thus, solid shafts having a nominal diameter from a large tolerance range are usable, because such diameter variations are accommodated by small axial shifts of adapter bushings 4, 11 and by the high elasticity along the periphery of adapter bushings 4, 11 as a result of axial longitudinal slot 21.

[0075]FIG. 2 shows a further exemplary embodiment according to the invention. In this case, the tightening of tightening screw 25 causes an axial setting and centering of the parts; namely, in response to the tightening, supporting disk 24 presses against adapter bushing 4, which in turn is pressed onto hollow shaft 3. Therefore, hollow shaft 3 is pressed against adapter bushing 11, and adapter bushing 11 is pressed against shoulder 22 of solid shaft 1.

[0076] In further exemplary embodiments of the present invention, adapter bushing 4 may be implemented with a cone angle which results in automatic locking or non-automatic locking of adapter bushing 4.

[0077] The property of automatic locking or non-automatic locking is determined by the selection of the cone angle of the outer cone of adapter bushing 4, the selection of the materials of the contacting parts such as adapter bushing 4, hollow shaft 1 or the like, and by the selection of the lubricant.

[0078] In a further such exemplary embodiment with non-automatic locking, tightening screw 25, together with supporting disk 24, produces a prestressing which is definable on the basis of the tightening torque, and additionally produces an axial, mechanical locking.

[0079] In other exemplary embodiments of the present invention, instead of supporting disk 24 and tightening screw 25, at least one retaining ring is used which is sunk into a groove in the solid shaft. In addition—depending on the specific special construction—shim rings are also usable. It is thus advantageously possible to produce the mechanical locking inexpensively using standard component parts. Given suitable dimensioning by one skilled in the art, even a prestressing is conceivable within the framework of the invention.

[0080] The invention also relates to devices which have no adapter bushing 11 and associated end stop 22.

[0081]FIG. 3 shows another exemplary embodiment according to the invention which, at the end facing the contraction disk, is like FIG. 1. Deviating from FIG. 1, however, is that solid shaft 1 is implemented without end stop 22. Thus, solid shaft 1 may be produced particularly easily. Clamping ring 26 is used for the axial fixation of adapter bushing 27. Since the clamping ring is used for the axial fixation and does not have to make a significant contribution to the transfer of torque and/or force, it may be implemented in a compact fashion and requires only a little, particularly axial, overall length. In addition, an inexpensive standard part is usable as the clamping ring. The connection for transmitting torque and/or force is provided, as also in the exemplary embodiments according to FIGS. 1 and 2, by the contraction disk and the associated adapter bushing there

[0082]FIG. 4 shows another exemplary embodiment according to the invention which, at the end facing the contraction disk, is like FIG. 2. Deviating from FIG. 2, however, solid shaft 1 is implemented without end stop 22. Clamping ring 26 is again used for the axial fixation of adapter bushing 27, the advantages corresponding to the aforesaid advantages.

[0083] In FIG. 5, the exemplary embodiment according to FIG. 3 is sketched in spatial representation. In so doing, the parts are sketched in an exploded view, thus are visible individually, pushed apart from each other. Clamping ring 26 is joined to adapter bushing 27 by the tightening of clamping screw 28, the distance at the periphery in the case of axial longitudinal slot 26.C, and therefore also the inside diameter of centering pressure bore hole 26.B being reduced. Clamping ring 26, with its centering pressure bore hole 26.B, contacts outer centering seat 27.B of adapter bushing 27, which with its centering cone 27.A is able to be joined to hollow shaft 3 at its inner cone. Slot 27.C of adapter bushing 27 permits a uniform contraction of adapter bushing 27 at the periphery. Contact surface 26.A forms the axial end stop for adapter bushing 27. In this context, care must be taken that the clamping ring has a suitable profile, which is shown in cross-section representation in FIG. 3 and FIG. 4. The profile has a gradation for forming the indicated end stop for adapter bushing 3, such that axially, the adapter bushing is only able to extend partially into the clamping ring. 

What is claimed is:
 1. A clamping mechanism for securing a hollow shaft 3 or a hollow part on a solid shaft 1, wherein the hollow shaft 3 or the hollow part, at at least one of it ends, has an inner cone for receiving an adapter bushing (4, 11, 27) which has a corresponding outer cone and rests on the solid shaft 1; at at least the one end, a contraction disk, including at least one pressure ring 5, is provided on the hollow shaft 3 or on the hollow part for exerting a contraction force.
 2. The clamping mechanism as recited in claim 1, wherein the hollow shaft 3 or the hollow part has in each case at both ends an inner cone for receiving a respective adapter bushing (4, 11, 27) which has a corresponding outer cone and rests on the solid shaft 1, in each case a contraction disk, including at least one pressure ring 5, being provided on the hollow shaft 3 or on the hollow part for exerting a contraction force.
 3. The clamping mechanism as recited in claim 1, wherein the hollow shaft 3 or the hollow part has in each case at both ends an inner cone for receiving a respective adapter bushing (4, 27) which has a corresponding outer cone and rests on the solid shaft 1, a clamping ring being provided at the other end for the axial fixation of the corresponding adapter bushing
 27. 4. The clamping mechanism as recited in at least one of the preceding claims, wherein the contraction force acts in such a way that the inner cone and the outer cone are shrunk onto each other.
 5. The clamping mechanism as recited in at least one of the preceding claims, wherein the contraction force acts on the hollow shaft 3 or the hollow part with the aid of the at least one pressure ring
 5. 6. The clamping mechanism as recited in at least one of the preceding claims, wherein the pressure ring 5 has an axial longitudinal slot
 23. 7. The clamping mechanism as recited in at least one of the preceding claims, wherein the adapter bushing (4, 11, 27) has an axial longitudinal slot
 21. 8. The clamping mechanism as recited in at least one of the preceding claims, wherein the hollow shaft 3 has no slot.
 9. The clamping mechanism as recited in at least one of the preceding claims, wherein the inner cone of the hollow shaft 3 is machined by grinding.
 10. The clamping mechanism as recited in at least one of the preceding claims, wherein the contraction disk includes at least one pressure ring 5, at least one bracing disk 6, at least one tightening disk 7 and at least screws
 8. 11. The clamping mechanism as recited in at least one of the preceding claims, wherein the contraction disk and/or the bracing disk 6 and/or the tightening disk 7 is/are located axially within the hollow shaft
 3. 12. The clamping mechanism as recited in at least one of the preceding claims, wherein the adapter bushing 4 has a collar formed in such a way that during disassembly, extraction is practicable with the aid of extraction disk
 7. 13. The clamping mechanism as recited in at least one of the preceding claims, wherein the extraction disk 7 has screw holes 19 for the screws 8 for tightening the contraction disk, particularly during assembly, and has further screw holes 20 for the disassembly, loosening the contraction disk and/or the extraction of at least the adapter bushing (4, 11, 27).
 14. The clamping mechanism as recited in at least one of the preceding claims, wherein the solid shaft has an end stop 22 for limiting the axial position of a further adapter bushing
 11. 15. The clamping mechanism as recited in at least one of the preceding claims, wherein the further adapter bushing 11 has an outer cone and/or a collar.
 16. The clamping mechanism as recited in at least one of the preceding claims, wherein the adapter bushing (4, 11, 27) is designed in such a way that it is self-locking with respect to the solid shaft 1 and/or hollow shaft
 3. 17. The clamping mechanism as recited in at least one of the preceding claims, wherein the adapter bushing (4, 11, 27) has a cone angle, such that it is self-locking with respect to the solid shaft 1 and/or hollow shaft
 3. 18. The clamping mechanism as recited in at least one of the preceding claims, wherein the outer cone of the adapter bushing (4, 11, 27) and/or the inner cone of the hollow shaft 3 or of the hollow part has a cone angle such that it is self-locking with respect to the solid shaft 1 and/or hollow shaft
 3. 19. The clamping mechanism as recited in at least one of claims 1 through 15, wherein the adapter bushing (4, 11, 27) is designed in such a way that it is not self-locking with respect to the solid shaft 1 and/or hollow shaft
 3. 20. The clamping mechanism as recited in at least one of claims 1 through 15 or 19, wherein the adapter bushing (4, 11, 27) has a cone angle, such that it is not self-locking with respect to the solid shaft 1 and/or hollow shaft
 3. 21. The clamping mechanism as recited in at least one of claims 1 through 15, 19 or 20, wherein the outer cone of the adapter bushing (4, 11, 27) and/or the inner cone of the hollow shaft 3 or of the hollow part has a cone angle such that it is not self-locking with respect to the solid shaft 1 and/or hollow shaft
 3. 22. The clamping mechanism as recited in at least one of the preceding claims, wherein a further component, including at least one individual component, acts on the solid shaft 1 in such a way and is able to be joined to the solid shaft 1 in such a way that the solid shaft 1 is axially positioned, locked and/or prestressed with respect to the hollow shaft 3 or the hollow part.
 23. The clamping mechanism as recited in at least one of the preceding claims, wherein the component produces an axial mechanical locking, at least when the adapter bushing (4, 11, 27) is not self-locking, and/or the cone angle of the outer cone of the adapter bushing (4, 11, 27), the materials and the lubricant are implemented for non-automatic locking of the adapter bushing (4, 11, 27) with respect to the hollow shaft 3 or the hollow part.
 24. The clamping mechanism as recited in at least one of the preceding claims, wherein the component includes tightening screw 25 and supporting disk 24 as individual components, and/or is mounted at one end of the hollow shaft 3 or of the hollow part.
 25. The clamping mechanism as recited in at least one of the preceding claims, wherein the component includes as individual component at least one retaining ring which is sunk into a groove in the solid shaft.
 26. The clamping mechanism as recited in at least one of the preceding claims, wherein the component also includes at least one shim ring as individual component.
 27. The clamping mechanism as recited in claim 22, wherein the joining is effected by a tightening, particularly of tightening screw
 25. 